Decaf English Breakfast Tea

Hi mummies, I’m wondering is it ok to drink a cup of decaf black tea every morning? I noticed for the past one week I had like 5 days of tea. Although the it’s decaf some people told me black tea have tannic so it’s still not good for my baby. I’m 18wks now, previously I try to drink only 2 times per week. Please advice :) thanks in advance 🥰